Objective: To determine the sensitivity, specificity, and positive and nega
tive predictive values of an enzymatic urine screening test for diagnosing
bacteriuria in pregnancy.
Methods: Clean-catch midstream urine samples were collected from 383 women
who had routine prenatal screening for bacteriuria. Sensitivity, specificit
y, and positive and negative predictive values for each screening test (enz
yme activity, nitrites or leukocytes on dipstick, and bacteria or pyuria on
microscopic examination) were estimated using urine culture as the criteri
on standard. Urine cultures were considered positive if they grew 10(4) col
ony-forming units of a single uropathogen. Standard deviations used to calc
ulate 95% confidence intervals were based on binomial distribution. A sampl
e of 30 urine specimens was selected to evaluate interrater agreement using
Cohen's kappa statistic.
Results: Five of 383 samples were contaminated, leaving 378 samples for eva
luation. Thirty of 43 specimens with positive urine culture had positive en
zyme activity. Of 335 samples with no growth, 150 had negative enzyme activ
ity. Sensitivity, specificity, and positive and negative predictive values
for the Uriscreen enzymatic screening test (Bard Patient Care Division, Mur
ray Hill, NJ) were 70%, 45%, 14%, and 92%, respectively. Sensitivity of the
Uriscreen was lower than that of bacteria alone. Interrater agreement for
Uriscreen testing was high among the three testers (K = .86).
Conclusion: The Uriscreen enzymatic screening test had inadequate sensitivi
ty for rapid screening for bacteriuria in pregnancy. (C) 2000 by The Americ
an College of Obstetricians and Gynecologists.